Make SVGLengthMode an enum class

Source/core/svg/SVGSVGElement.cpp

Index: Source/core/svg/SVGSVGElement.cpp
diff --git a/Source/core/svg/SVGSVGElement.cpp b/Source/core/svg/SVGSVGElement.cpp
index 005ed8c7d38bb405c953a375dfae50bac1170a58..117feddae61fc20df439d2b6fcc9de39126e8dce 100644
--- a/Source/core/svg/SVGSVGElement.cpp
+++ b/Source/core/svg/SVGSVGElement.cpp
@@ -61,10 +61,10 @@ namespace blink {
 
 inline SVGSVGElement::SVGSVGElement(Document& doc)
     : SVGGraphicsElement(SVGNames::svgTag, doc)
-    , m_x(SVGAnimatedLength::create(this, SVGNames::xAttr, SVGLength::create(LengthModeWidth), AllowNegativeLengths))
-    , m_y(SVGAnimatedLength::create(this, SVGNames::yAttr, SVGLength::create(LengthModeHeight), AllowNegativeLengths))
-    , m_width(SVGAnimatedLength::create(this, SVGNames::widthAttr, SVGLength::create(LengthModeWidth), ForbidNegativeLengths))
-    , m_height(SVGAnimatedLength::create(this, SVGNames::heightAttr, SVGLength::create(LengthModeHeight), ForbidNegativeLengths))
+    , m_x(SVGAnimatedLength::create(this, SVGNames::xAttr, SVGLength::create(SVGLengthMode::Width), AllowNegativeLengths))
+    , m_y(SVGAnimatedLength::create(this, SVGNames::yAttr, SVGLength::create(SVGLengthMode::Height), AllowNegativeLengths))
+    , m_width(SVGAnimatedLength::create(this, SVGNames::widthAttr, SVGLength::create(SVGLengthMode::Width), ForbidNegativeLengths))
+    , m_height(SVGAnimatedLength::create(this, SVGNames::heightAttr, SVGLength::create(SVGLengthMode::Height), ForbidNegativeLengths))
     , m_useCurrentView(false)
     , m_timeContainer(SMILTimeContainer::create(*this))
     , m_translation(SVGPoint::create())